1. Field of the Invention
This invention relates to a device for protection of computer software installed on hard disks against unauthorized copying and use, and particularly a device of such type that is embedded inside a diskette cartridge.
2. Important Notice to the Reader of this Patent Application
This patent application describes a device of a relatively simple physical structure. However, the mechanism by which the device performs its function is new and of considerable complexity.
Every effort has been made to keep the specification clear and understandable. However, patience and concentration in reading are necessary for understanding.
The section titled "Software protection in the same workplace" is the most important section of this application and should be read with special care.
3. Description of the Related Art
Each year, billions of dollars worth of American software is stolen overseas. This not only hurts the American software developers, but is also extremely damaging to the U.S. economy, one of its key elements of strength being technology.
In one country half-the-way around the globe, I saw a software merchant advertising: "We sell the latest version of AutoCad for 15 pounds".
Software theft has become a widely spread phenomenon in recent years due to the extreme ease with which data can be transferred among magnetic media, and the lack of successful means for preventing unauthorized data transfers.
It is the object of the present invention to provide such successful device for preventing software theft. The device is an intelligent diskette that accompanies each set of executable diskettes. Without the presence of that device, execution of the code on the CPU is impossible.
In the prior art, several techniques have been developed in attempts to prevent software theft, none of which has been completely successful to date. The first attempt was to alter the standard format of storing files on the magnetic media to prevent unauthorized duplication. But rapidly programs were developed to break this copy-protection scheme. Another attempt was to provide an intelligent circuit that connects to the computer via a serial port or internal bus. Unfortunately, however, such circuits can easily be duplicated by professionals, as they usually depend on a ROM which can be duplicated by various means. Further, the use of an additional piece of hardware for each software program is very inconvenient for the user.
A third technique is described in U.S. Pat. No. 4,734,796 issued Mar. 29, 1988 to Grynberg et al, which shows a method for preventing unauthorized copying of diskettes based on inducing surface defects at known locations on the magnetic media. A still further technique is shown in U.S. Pat. Nos. 4,858,036 and 4,980,782 issued Aug. 15, 1989 and Dec. 25, 1990, respectively, to Peter Ginkel, which depends on the use of magnetic materials possessing high coercivity to prevent duplication of diskettes.
Unfortunately, however, the techniques of those three patents are still vulnerable to unauthorized copying by professionals. Further, once the executable code is installed on a hard disk (as is usually the case), such protection methods are worthless.
It is the objective of the present invention to provide a device for preventing the use of stolen software. Since "copy-protection" techniques have failed to prevent software theft, the present invention rather prevents the execution of the code on the CPU, unless the device of the invention is present in the floppy disk drive of the computer.
It is another objective of the present invention to provide a method for software protection which is extremely convenient for the end user, by featuring an ordinary diskette cartridge that can be easily loaded in the disk drive of the computer each time the software is run.
It is finally the ultimate objective of the present invention to provide a method and device for software protection which will prevent an executable code from being installed on more than one machine, even if several machines are present in the same workplace.
Other aspects and features of the invention will be more fully apparent from the ensuing disclosure and appended claims.